Having just been on a plane, there is no way anyone could have seen London or France the way those seats are designed. But yikes, why would you dress like that? Those are always the people that complain about being cold too.
But to be thrown off for it? that sounds kind of strange. Unless you were showing private areas, I would think it would matter really. I guess she was showing those areas, but again, in an airplane seat, who's going to see it? You can't even cross your legs because of the closeness of the seats in front of you.